1. Field of Invention
The invention relates to a fan, a motor and an impeller, and, in particular, to a fan, a motor and an impeller with good heat dissipation ability.
2. Related Art
With the rapid development of electronic products toward increasing performance, frequency, and speed, as well as increasing demand for compact, slim-profile, lightweight devices, the operating temperature of electronic products is correspondingly increasing. Due to this trend, there is also an increase in unstable heat-aggravated phenomena that influence product reliability. Therefore, current electronic products are often equipped with a fan that serves as a heat-dissipation device.
Referring to FIG. 1, a conventional fan 1 includes an impeller 11, a motor 12 and a frame 13. The impeller 11 includes a hub 111 and a plurality of blades 112 disposed around the hub 111. The motor 12 is accommodated in the hub 111, and is connected with the impeller 11 to drive the rotation of impeller 11. The impeller 11 and the motor 12 are disposed in the frame 13. The fan 1 encapsulates a top portion 1111 of the hub 111 to prevent foreign objects from entering the hub 111 in order to protect the motor 12. However, this causes the heat dissipated by the motor 12 to be restricted to the hub 111 and thus the heat-dissipating effect is poor. Thus, the efficiency of the fan 1 may deteriorate due to the greatly increased environmental temperature after a long period of operation.
Referring to FIG. 2, another conventional fan 2 includes an impeller 21, a motor 22 and a frame 23. The impeller 21 includes a hub 211 and a plurality of blades 212 disposed around the hub 211. The motor 22 is accommodated in the hub 211 and is connected with the impeller 21 to drive the rotation of impeller 21. The impeller 21 and the motor 22 are disposed in the frame 23. Atop portion 2111 of the hub 211 has an opening 2112 to expose a conducting shell 221 of the motor 22. The exposed portion of the conducting shell 221 has a plurality of holes 2211, through which the airflow “a” enters the motor 22 to dissipate the heat produced by the motor 22. However, foreign objects or dust may also fall down into the motor 22 and damage the motor as the airflow “a” flows through the holes 2211.
Thus, it is an important subject of the invention to provide a fan, a motor and an impeller capable of solving the problems of dissipating motor-generated heat and preventing foreign objects from entering the motor, thus enhancing the fan efficiency.